Authoritative sources within the bike industry are claiming that the 2013 bicycle model year - that's this time next year for actual shipments - will feature an 11-speed transmission for Shimano's flagship Dura-Ace Di2 groupset along with optional disc brakes actuated from a familiar-looking multi-purpose brake and shift lever.

The 11-speed makes sense for two reasons; first that with the free availability by then of the less expensive Ultegra Di2 components - and possibly an even cheaper 105 version on the horizon - the Japanese manufacturer will be looking to reassert Dura-Ace's differentiation at the top of the component food chain. More on Ultegra Di2 availability in a moment, however.

Second, that much as it will pain them to admit it after Campagnolo has had three seasons by then to sell the advantages of the closer-packed gear ratios, squeezing eleven sprockets into the space of ten really is just an evolution in engineering terms. This is one situation where playing second-fiddle to the Italians has served to prepare the way for the inevitable.

The disc brakes won't be any surprise to anyone who's been watching the development of carbon forks with disc mounts over the last few years with all the talk so far being of racing cyclo-cross. Indeed, all the forks seen so far - 3T's Luteus for example - are specifically designed for 'cross; rough pounding, mud clearance and all. But it does raise the question of how relatively simple it would be to redesign a carbon fork for smooth tarmac after the rigours of 'cross.

Will the discs be hydraulic or cable? Not everyone seems to be agreed on that, as far as we can see the only thing stopping you running cable discs with Di2 now is having the necessary frame/fork mounting points - hydraulics would be a step forward worth shouting about and as we've seen with the latest hydraulic converters for drop bars the technology required to run hydraulic discs with a drop bar is rapidly getting small enough where the idea of sticking it inside a lever hood is looking increasingly doable.

We cannot see the UCI changing the rule for disc brakes on WorldTour team bikes any time soon but this could be a situation where enthusiastic sportivistes could be prepared to go off alone from cycling's UCI-strangled equivalent of F1 if disc brakes offer a clear and unequivocal improvement in performance over rim calipers. And they will. Paul Lew, the carbon engineer from Reynolds Wheels who only designs bicycle rims for amusement when he's not drawing supersonic aircraft, said as much at Eurobike when we asked him why we couldn't have more tubeless road rims along the lines currently on offer for 29er mountain bikes but really light.

The calipers themselves are a no-brainer for anyone who has seen a Shimano XTR mountain bike brake. Presumably the largest 200mm+ discs used on downhill bikes won't be necessary with 160mm being the likely size for road, more than capable of providing the degree of modulation which is the big story with disc brakes and arguably an even bigger one when you're coping with such a small rubber contact patch on the road.

By the way, this won't be for the next launch or even the one after that but the marriage of electronics and disc brakes is inevitably setting off thoughts of ABS to us but that really is just speculation at this point.

One thing for sure because Shimano told us already they were doing it back at the Ultegra Di2 launch is that they will take the opportunity of the 11-speed launch to update the electronic brain and cable set to the fully digital and thinner 2-core protocol used for Ultegra.

Finally, and thinking of Ultegra, we're hearing from disgruntled customers that having been originally promised their new Di2 groupsets in mid-October - ie now - they've been warned by major retailers that their orders won't be filled until December or even January. Could it be that the bike manufacturers have been upping their orders and applying the pressure now that interest in the new set seems to have caught fire?

adding disc brakes for road bikes should lead to better stopping power, especially compared to what we currently get with carbon rims. plus, the lifetime of those expensive wheels will be extended because the brakes won't eat up the rims like they do on current brake tracks. rims will be lighter too. later on, hydraulics should bring the weight down a little bit to, compared to mechanical systems. i'm looking forward to them myself.

I'm sorry but putting disc brakes on a road bike is the same as painting the Mona Lisa with ginger hair and a moustache.

What would be a much more aestetically pleasing forward development would be for a compact hydraulic rim brake to be deveolped that doesn't look much more obtrusive than a current caliper and for carbon rim manufacturers to learn how to make some sort of laminate that protects carbon rims from wear and heat build up.

Being shimano i cant see them sticking to 160mm rotors. Look out for another rotor mounting 'standard' for hub, centrelock lite maybe? and super small rotors, 130mm rear? 150mm front? Hope used to produce the XC4 in 150/130 sizes and they were just about ok, so i dont see BigS staying big just because thats what is out already.

Combine in ICE-Tech brake surfaces or ceramic coated alu (for race day) and finned pads for cooling, you have a seriously compact/light but performance brake. Look at what magura and formula are producing now for top level XC brakes and imagine that squeezed down with a bit more shimano design polish and you will probably be close i reckon.

I like the idea of super light disc-specific rims. Must be able to build a wheel with these with less rotating inertia, even if the overall weight ends up a bit higher.

Probably never see them in use in road racing (if the UCI ever permitted them) since disc wheels can be a bit fiddly to mount. Imagine a panicked mechanic failing to do a fast wheel swap. And the disc on neutral service wheels would be bound to rub too!

I'm sorry but putting disc brakes on a road bike is the same as painting the Mona Lisa with ginger hair and a moustache.

Really? Come on, it's not that bad! Do you feel that way about STI levers, oversize BBs etc? I guess a pannier rack would be an abomination.

I think you can have 'discreet' discs (see STATO's post), and for those of us riding all year round looks are something of a minor point compared to the likely benefits in braking performance when you really need it.

The MTB market has refined pad/disc technology so that only the most curmudgeonly of offroad riders would choose rim brakes over disc. If you've ridden on discs for a while perhaps you could forgive the disfigurement for the benefit(s).

cat1commuter wrote:

I like the idea of super light disc-specific rims. Must be able to build a wheel with these with less rotating inertia, even if the overall weight ends up a bit higher.

I don't see a small reduction in rim weight making a huge difference, to be honest. A lightweight rim is only 350-400g, how much would you save - half a fruit bar's worth? Chasing one's tail IMHO. Braking efficiency and modulation, particularly in the wet, is much more attractive to me. Increased rim life is undoubtedly a good thing, though the likes of Mavic might not agree.

As for 11-speed groupsets, well it's "one louder", or more accurately oneupmanship. It means more expensive chains and cassettes. 100% fine for those who want and can afford it but the concept is wasted on someone who feels 9 cogs on a cassette is plenty. After all, you still have to pedal it, however many gears you have.

The real problem with disc brakes on a road bike is torque. A radial spoked front wheel simply won't work. So unless every starts using cross 3 front wheels or some radical new wheel design, there is zero chance of seeing these on road bikes.

Discs increase the rotating mass of the wheel, even if the disc itself is only 62g, there's the increase in hub material required to support the braking power, which will push up the over-all weight that a rider has to turn. Overall you might be looking at an increase of 100g per wheel (not including the frame-fixed calliper) added to the rotating mass. Fine if you're descending, but not so nice when climbing.

i'm not an engineer or owt, but my understanding of the inertia of rotating bodies is that the moment of inertia is proportional to the square of the distance from the centre.

That being the case, if we assume that the mass of the disc (let's say 100g to take into account the beefier hub) has a centre of mass halfway out to the edge of the rotor, say 75mm, and the centre of mass of the rim is at 300mm from the centre, then by my dumbed down calculation that would mean that you'd need to save 25g from the rim to compensate for the extra 100g at the hub and keep the same moment of inertia. That seems achievable to me, given that you don't need to have a wearable braking surface.

On the other hand, you'll need to start using crossed spoke patterns again, like imaca says. that will probably mean higher spoke counts and a bit of extra weight at the front. rear wheels use crossed spokes anyway.

How often do road cyclists actually need the dependability and modulation of disc brakes though? Having had a disc equipped MTB before my current road bike with Ultegra calipers, I was pleasantly surprised by how good a set of well set up callipers are. Unless you're doing a particularly muddy Paris Roubaix I suspect the benefits will be outweighed by cost/weight/aerodynamics/aesthetics/fettling time.

rim brakes are such an anachronism I think it's just a matter of time before we see them refined for racing road bikes - because that's what we're talking about here, not the commuter, tour, utility bike market who are more practically orientated.

All it will take is a decent looking setup to be adopted by a few pro-riders and it'll be the new must-have and rim brakes will look so last-season.

However I can't think of a situation where I thought I needed more braking power - I can already brake hard enough to throw myself over the bars if I need to.

Disc brakes give improved modulation, not more power. On a road bike power will always be limited by the relatively small contact patch of the tyre to the road. ie: Disc brakes should allow you to brake harder without skidding.

Just speaking from experience, as i have feet in both camps (mtb and road) whenever i ride my mountain bike i always enjoy the power and control of the hydraulic discs...something i cant say about the rim brakes on my bianchi. frankly they scare the bejesus out of me. they have very little "feel" and they really are not very effective. I'm 11 and a half stone and i'd like to feel that they'd stop me well,but they just dont.(in the wet they are worse)
to be fair,i have'nt tried any different blocks or compounds,and i know that there are better out there (swisstop,etc)but i cant help but love the discs,they are soooo good,ugly or not. If they make em for road bikes ....i want them!

Take enough material and therefore strength away from a frame and it will not transmit a rider’s power as efficiently, and therefore be slower

I'm not saying that's not the case; i completely agree. but if that's your position, you can't then say that discs are bad because they make a bike heavier. because like you say, lighter isn't necessarily better.

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Why do you need to the power of disc brakes on a road bike? Complete waste of time, not to mention ugly

I remember similar arguments being forwarded for mountain bikes. and cyclocross bikes, and urban bikes. it's not really about power, it's about consistent, well modulated braking performance, in all conditions. discs are better at that. in a race, that could be a competitive advantage. time will tell whether the pros think so, i guess.

I am wondering whether we are to expect a new front axle standard to go with the disk brakes.

There is the (still unproven) issue of braking torque ripping the front wheel out of the dropouts - as alleged in the then-widely-publicised Russell Pinder case. This Singletrack Forum Thread has most of the info.

I've been riding MTBs for 15 years, and never had any wheel ejection problems, even with 203mm rotors on QR dropouts - but the introduction of 20mm and then 15mm both-through axles has definitely negated the risk - not to mention improved front-end accuracy.

Of course road bike forks don't have the issue of moving parts to introduce flex - but a closed-bottom dropout would prevent any potential issues.

Of course, it'll have to be quick to remove in a race-puncture situation.

The other concern is the potential for 'branding' in a crash. I know 2 MTBers who've got too close to their disks after dismounting at the bottom of a long descent and have the burn scars on their calves to prove it!